1 ;;;; structures for the first intermediate representation in the
4 ;;;; This software is part of the SBCL system. See the README file for
7 ;;;; This software is derived from the CMU CL system, which was
8 ;;;; written at Carnegie Mellon University and released into the
9 ;;;; public domain. The software is in the public domain and is
10 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
11 ;;;; files for more information.
15 ;;; The front-end data structure (IR1) is composed of nodes and
16 ;;; continuations. The general idea is that continuations contain
17 ;;; top-down information and nodes contain bottom-up, derived
18 ;;; information. A continuation represents a place in the code, while
19 ;;; a node represents code that does something.
21 ;;; This representation is more of a flow-graph than an augmented
22 ;;; syntax tree. The evaluation order is explicitly represented in the
23 ;;; linkage by continuations, rather than being implicit in the nodes
24 ;;; which receive the the results of evaluation. This allows us to
25 ;;; decouple the flow of results from the flow of control. A
26 ;;; continuation represents both, but the continuation can represent
27 ;;; the case of a discarded result by having no DEST.
29 (def!struct (continuation
30 (:make-load-form-fun ignore-it)
31 (:constructor make-continuation (&optional dest)))
32 ;; an indication of the way that this continuation is currently used
35 ;; A continuation for which all control-related slots have the
36 ;; default values. A continuation is unused during IR1 conversion
37 ;; until it is assigned a block, and may be also be temporarily
38 ;; unused during later manipulations of IR1. In a consistent
39 ;; state there should never be any mention of :UNUSED
40 ;; continuations. Next can have a non-null value if the next node
41 ;; has already been determined.
44 ;; A continuation that has been deleted from IR1. Any pointers into
45 ;; IR1 are cleared. There are two conditions under which a deleted
46 ;; continuation may appear in code:
47 ;; -- The CONT of the LAST node in a block may be a deleted
48 ;; continuation when the original receiver of the continuation's
49 ;; value was deleted. Note that DEST in a deleted continuation is
50 ;; null, so it is easy to know not to attempt delivering any
51 ;; values to the continuation.
52 ;; -- Unreachable code that hasn't been deleted yet may receive
53 ;; deleted continuations. All such code will be in blocks that
54 ;; have DELETE-P set. All unreachable code is deleted by control
55 ;; optimization, so the backend doesn't have to worry about this.
58 ;; The continuation that is the START of BLOCK. This is the only kind
59 ;; of continuation that can have more than one use. The BLOCK's
60 ;; START-USES is a list of all the uses.
62 ;; :DELETED-BLOCK-START
63 ;; Like :BLOCK-START, but BLOCK has been deleted. A block
64 ;; starting continuation is made into a deleted block start when
65 ;; the block is deleted, but the continuation still may have
66 ;; value semantics. Since there isn't any code left, next is
70 ;; A continuation that is the CONT of some node in BLOCK.
71 (kind :unused :type (member :unused :deleted :inside-block :block-start
72 :deleted-block-start))
73 ;; The node which receives this value, if any. In a deleted
74 ;; continuation, this is null even though the node that receives
75 ;; this continuation may not yet be deleted.
76 (dest nil :type (or node null))
77 ;; If this is a NODE, then it is the node which is to be evaluated
78 ;; next. This is always null in :DELETED and :UNUSED continuations,
79 ;; and will be null in a :INSIDE-BLOCK continuation when this is the
81 (next nil :type (or node null))
82 ;; an assertion on the type of this continuation's value
83 (asserted-type *wild-type* :type ctype)
84 ;; cached type of this continuation's value. If NIL, then this must
85 ;; be recomputed: see CONTINUATION-DERIVED-TYPE.
86 (%derived-type nil :type (or ctype null))
87 ;; Node where this continuation is used, if unique. This is always
88 ;; null in :DELETED and :UNUSED continuations, and is never null in
89 ;; :INSIDE-BLOCK continuations. In a :BLOCK-START continuation, the
90 ;; Block's START-USES indicate whether NIL means no uses or more
92 (use nil :type (or node null))
93 ;; the basic block this continuation is in. This is null only in
94 ;; :DELETED and :UNUSED continuations. Note that blocks that are
95 ;; unreachable but still in the DFO may receive deleted
96 ;; continuations, so it isn't o.k. to assume that any continuation
97 ;; that you pick up out of its DEST node has a BLOCK.
98 (block nil :type (or cblock null))
99 ;; set to true when something about this continuation's value has
100 ;; changed. See REOPTIMIZE-CONTINUATION. This provides a way for IR1
101 ;; optimize to determine which operands to a node have changed. If
102 ;; the optimizer for this node type doesn't care, it can elect not
103 ;; to clear this flag.
104 (reoptimize t :type boolean)
105 ;; an indication of what we have proven about how this contination's
106 ;; type assertion is satisfied:
109 ;; No type check is necessary (proven type is a subtype of the assertion.)
112 ;; A type check is needed.
115 ;; Don't do a type check, but believe (intersect) the assertion.
116 ;; A T check can be changed to :DELETED if we somehow prove the
117 ;; check is unnecessary, or if we eliminate it through a policy
121 ;; Type check generation sets the slot to this if a check is
122 ;; called for, but it believes it has proven that the check won't
123 ;; be done for policy reasons or because a safe implementation
124 ;; will be used. In the latter case, LTN must ensure that a safe
125 ;; implementation *is* used.
128 ;; There is a compile-time type error in some use of this
129 ;; continuation. A type check should still be generated, but be
132 ;; This is computed lazily by CONTINUATION-DERIVED-TYPE, so use
133 ;; CONTINUATION-TYPE-CHECK instead of the %'ed slot accessor.
134 (%type-check t :type (member t nil :deleted :no-check :error))
135 ;; something or other that the back end annotates this continuation with
137 ;; uses of this continuation in the lexical environment. They are
138 ;; recorded so that when one continuation is substituted for another
139 ;; the environment may be updated properly.
140 (lexenv-uses nil :type list))
142 (def!method print-object ((x continuation) stream)
143 (print-unreadable-object (x stream :type t :identity t)))
145 (defstruct (node (:constructor nil)
147 ;; the bottom-up derived type for this node. This does not take into
148 ;; consideration output type assertions on this node (actually on its CONT).
149 (derived-type *wild-type* :type ctype)
150 ;; True if this node needs to be optimized. This is set to true
151 ;; whenever something changes about the value of a continuation
152 ;; whose DEST is this node.
153 (reoptimize t :type boolean)
154 ;; the continuation which receives the value of this node. This also
155 ;; indicates what we do controlwise after evaluating this node. This
156 ;; may be null during IR1 conversion.
157 (cont nil :type (or continuation null))
158 ;; the continuation that this node is the next of. This is null
159 ;; during IR1 conversion when we haven't linked the node in yet or
160 ;; in nodes that have been deleted from the IR1 by UNLINK-NODE.
161 (prev nil :type (or continuation null))
162 ;; the lexical environment this node was converted in
163 (lexenv *lexenv* :type lexenv)
164 ;; a representation of the source code responsible for generating
167 ;; For a form introduced by compilation (does not appear in the
168 ;; original source), the path begins with a list of all the
169 ;; enclosing introduced forms. This list is from the inside out,
170 ;; with the form immediately responsible for this node at the head
173 ;; Following the introduced forms is a representation of the
174 ;; location of the enclosing original source form. This transition
175 ;; is indicated by the magic ORIGINAL-SOURCE-START marker. The first
176 ;; element of the original source is the "form number", which is the
177 ;; ordinal number of this form in a depth-first, left-to-right walk
178 ;; of the truly top-level form in which this appears.
180 ;; Following is a list of integers describing the path taken through
181 ;; the source to get to this point:
182 ;; (K L M ...) => (NTH K (NTH L (NTH M ...)))
184 ;; The last element in the list is the top-level form number, which
185 ;; is the ordinal number (in this call to the compiler) of the truly
186 ;; top-level form containing the original source.
187 (source-path *current-path* :type list)
188 ;; If this node is in a tail-recursive position, then this is set to
189 ;; T. At the end of IR1 (in physical environment analysis) this is
190 ;; computed for all nodes (after cleanup code has been emitted).
191 ;; Before then, a non-null value indicates that IR1 optimization has
192 ;; converted a tail local call to a direct transfer.
194 ;; If the back-end breaks tail-recursion for some reason, then it
195 ;; can null out this slot.
196 (tail-p nil :type boolean))
198 ;;; Flags that are used to indicate various things about a block, such
199 ;;; as what optimizations need to be done on it:
200 ;;; -- REOPTIMIZE is set when something interesting happens the uses of a
201 ;;; continuation whose Dest is in this block. This indicates that the
202 ;;; value-driven (forward) IR1 optimizations should be done on this block.
203 ;;; -- FLUSH-P is set when code in this block becomes potentially flushable,
204 ;;; usually due to a continuation's DEST becoming null.
205 ;;; -- TYPE-CHECK is true when the type check phase should be run on this
206 ;;; block. IR1 optimize can introduce new blocks after type check has
207 ;;; already run. We need to check these blocks, but there is no point in
208 ;;; checking blocks we have already checked.
209 ;;; -- DELETE-P is true when this block is used to indicate that this block
210 ;;; has been determined to be unreachable and should be deleted. IR1
211 ;;; phases should not attempt to examine or modify blocks with DELETE-P
212 ;;; set, since they may:
213 ;;; - be in the process of being deleted, or
214 ;;; - have no successors, or
215 ;;; - receive :DELETED continuations.
216 ;;; -- TYPE-ASSERTED, TEST-MODIFIED
217 ;;; These flags are used to indicate that something in this block
218 ;;; might be of interest to constraint propagation. TYPE-ASSERTED
219 ;;; is set when a continuation type assertion is strengthened.
220 ;;; TEST-MODIFIED is set whenever the test for the ending IF has
221 ;;; changed (may be true when there is no IF.)
222 (def-boolean-attribute block
223 reoptimize flush-p type-check delete-p type-asserted test-modified)
225 (macrolet ((frob (slot)
226 `(defmacro ,(symbolicate "BLOCK-" slot) (block)
227 `(block-attributep (block-flags ,block) ,',slot))))
233 (frob test-modified))
235 ;;; The CBLOCK structure represents a basic block. We include
236 ;;; SSET-ELEMENT so that we can have sets of blocks. Initially the
237 ;;; SSET-ELEMENT-NUMBER is null, DFO analysis numbers in reverse DFO.
238 ;;; During IR2 conversion, IR1 blocks are re-numbered in forward emit
239 ;;; order. This latter numbering also forms the basis of the block
240 ;;; numbering in the debug-info (though that is relative to the start
241 ;;; of the function.)
242 (defstruct (cblock (:include sset-element)
243 (:constructor make-block (start))
244 (:constructor make-block-key)
247 (:copier copy-block))
248 ;; a list of all the blocks that are predecessors/successors of this
249 ;; block. In well-formed IR1, most blocks will have one successor.
250 ;; The only exceptions are:
251 ;; 1. component head blocks (any number)
252 ;; 2. blocks ending in an IF (1 or 2)
253 ;; 3. blocks with DELETE-P set (zero)
254 (pred nil :type list)
255 (succ nil :type list)
256 ;; the continuation which heads this block (either a :BLOCK-START or
257 ;; :DELETED-BLOCK-START), or NIL when we haven't made the start
258 ;; continuation yet (and in the dummy component head and tail
260 (start nil :type (or continuation null))
261 ;; a list of all the nodes that have START as their CONT
262 (start-uses nil :type list)
263 ;; the last node in this block. This is NIL when we are in the
264 ;; process of building a block (and in the dummy component head and
266 (last nil :type (or node null))
267 ;; the forward and backward links in the depth-first ordering of the
268 ;; blocks. These slots are NIL at beginning/end.
269 (next nil :type (or null cblock))
270 (prev nil :type (or null cblock))
271 ;; This block's attributes: see above.
272 (flags (block-attributes reoptimize flush-p type-check type-asserted
275 ;; CMU CL had a KILL slot here, documented as "set used by
276 ;; constraint propagation", which was used in constraint propagation
277 ;; as a list of LAMBDA-VARs killed, and in copy propagation as an
278 ;; SSET, representing I dunno what. I (WHN) found this confusing,
279 ;; and furthermore it caused type errors when I was trying to make
280 ;; the compiler produce fully general LAMBDA functions directly
281 ;; (instead of doing as CMU CL always did, producing extra little
282 ;; functions which return the LAMDBA you need) and therefore taking
283 ;; a new path through the compiler. So I split this into two:
284 ;; KILL-LIST = list of LAMBDA-VARs killed, used in constraint propagation
285 ;; KILL-SSET = an SSET value, used in copy propagation
286 (kill-list nil :type list)
287 (kill-sset nil :type (or sset null))
288 ;; other sets used in constraint propagation and/or copy propagation
292 ;; the component this block is in, or NIL temporarily during IR1
293 ;; conversion and in deleted blocks
294 (component *current-component* :type (or component null))
295 ;; a flag used by various graph-walking code to determine whether
296 ;; this block has been processed already or what. We make this
297 ;; initially NIL so that FIND-INITIAL-DFO doesn't have to scan the
298 ;; entire initial component just to clear the flags.
300 ;; some kind of info used by the back end
302 ;; If true, then constraints that hold in this block and its
303 ;; successors by merit of being tested by its IF predecessor.
304 (test-constraint nil :type (or sset null)))
305 (def!method print-object ((cblock cblock) stream)
306 (print-unreadable-object (cblock stream :type t :identity t)
307 (format stream ":START c~D" (cont-num (block-start cblock)))))
309 ;;; The BLOCK-ANNOTATION class is inherited (via :INCLUDE) by
310 ;;; different BLOCK-INFO annotation structures so that code
311 ;;; (specifically control analysis) can be shared.
312 (defstruct (block-annotation (:constructor nil)
314 ;; The IR1 block that this block is in the INFO for.
315 (block (required-argument) :type cblock)
316 ;; the next and previous block in emission order (not DFO). This
317 ;; determines which block we drop though to, and also used to chain
318 ;; together overflow blocks that result from splitting of IR2 blocks
319 ;; in lifetime analysis.
320 (next nil :type (or block-annotation null))
321 (prev nil :type (or block-annotation null)))
323 ;;; A COMPONENT structure provides a handle on a connected piece of
324 ;;; the flow graph. Most of the passes in the compiler operate on
325 ;;; COMPONENTs rather than on the entire flow graph.
326 (defstruct (component (:copier nil))
327 ;; the kind of component
329 ;; (The terminology here is left over from before
330 ;; sbcl-0.pre7.34.flaky5.2, when there was no such thing as
331 ;; FUNCTIONAL-HAS-EXTERNAL-REFERENCES-P, so that Python was
332 ;; incapable of building standalone :EXTERNAL functions, but instead
333 ;; had to implement things like #'CL:COMPILE as FUNCALL of a little
334 ;; toplevel stub whose sole purpose was to return an :EXTERNAL
337 ;; The possibilities are:
339 ;; an ordinary component, containing non-top-level code
341 ;; a component containing only load-time code
342 ;; :COMPLEX-TOP-LEVEL
343 ;; In the old system, before FUNCTIONAL-HAS-EXTERNAL-REFERENCES-P
344 ;; was defined, this was necessarily a component containing both
345 ;; top-level and run-time code. Now this state is also used for
346 ;; a component with HAS-EXTERNAL-REFERENCES-P functionals in it.
348 ;; the result of initial IR1 conversion, on which component
349 ;; analysis has not been done
351 ;; debris left over from component analysis
353 ;; See also COMPONENT-TOP-LEVELISH-P.
354 (kind nil :type (member nil :top-level :complex-top-level :initial :deleted))
355 ;; the blocks that are the dummy head and tail of the DFO
357 ;; Entry/exit points have these blocks as their
358 ;; predecessors/successors. Null temporarily. The start and return
359 ;; from each non-deleted function is linked to the component head
360 ;; and tail. Until physical environment analysis links NLX entry
361 ;; stubs to the component head, every successor of the head is a
362 ;; function start (i.e. begins with a BIND node.)
363 (head nil :type (or null cblock))
364 (tail nil :type (or null cblock))
365 ;; This becomes a list of the CLAMBDA structures for all functions
366 ;; in this component. OPTIONAL-DISPATCHes are represented only by
367 ;; their XEP and other associated lambdas. This doesn't contain any
368 ;; deleted or LET lambdas.
370 ;; Note that logical associations between CLAMBDAs and COMPONENTs
371 ;; seem to exist for a while before this is initialized. In
372 ;; particular, I got burned by writing some code to use this value
373 ;; to decide which components need LOCAL-CALL-ANALYZE, when it turns
374 ;; out that LOCAL-CALL-ANALYZE had a role in initializing this value
375 ;; (and DFO stuff does too, maybe). Also, even after it's
376 ;; initialized, it might change as CLAMBDAs are deleted or merged.
378 (lambdas () :type list)
379 ;; a list of FUNCTIONAL structures for functions that are newly
380 ;; converted, and haven't been local-call analyzed yet. Initially
381 ;; functions are not in the LAMBDAS list. LOCAL-CALL-ANALYZE moves
382 ;; them there (possibly as LETs, or implicitly as XEPs if an
383 ;; OPTIONAL-DISPATCH.) Between runs of LOCAL-CALL-ANALYZE there may
384 ;; be some debris of converted or even deleted functions in this
386 (new-functions () :type list)
387 ;; If this is true, then there is stuff in this component that could
388 ;; benefit from further IR1 optimization.
389 (reoptimize t :type boolean)
390 ;; If this is true, then the control flow in this component was
391 ;; messed up by IR1 optimizations, so the DFO should be recomputed.
392 (reanalyze nil :type boolean)
393 ;; some sort of name for the code in this component
394 (name "<unknown>" :type simple-string)
395 ;; some kind of info used by the back end
397 ;; the SOURCE-INFO structure describing where this component was
399 (source-info *source-info* :type source-info)
400 ;; count of the number of inline expansions we have done while
401 ;; compiling this component, to detect infinite or exponential
403 (inline-expansions 0 :type index)
404 ;; a map from combination nodes to things describing how an
405 ;; optimization of the node failed. The description is an alist
406 ;; (TRANSFORM . ARGS), where TRANSFORM is the structure describing
407 ;; the transform that failed, and ARGS is either a list of format
408 ;; arguments for the note, or the FUN-TYPE that would have
409 ;; enabled the transformation but failed to match.
410 (failed-optimizations (make-hash-table :test 'eq) :type hash-table)
411 ;; This is similar to NEW-FUNCTIONS, but is used when a function has
412 ;; already been analyzed, but new references have been added by
413 ;; inline expansion. Unlike NEW-FUNCTIONS, this is not disjoint from
414 ;; COMPONENT-LAMBDAS.
415 (reanalyze-functions nil :type list))
416 (defprinter (component :identity t)
418 (reanalyze :test reanalyze))
420 ;;; Before sbcl-0.7.0, there were :TOP-LEVEL things which were magical
421 ;;; in multiple ways. That's since been refactored into the orthogonal
422 ;;; properties "optimized for locall with no arguments" and "externally
423 ;;; visible/referenced (so don't delete it)". The code <0.7.0 did a lot
424 ;;; of tests a la (EQ KIND :TOP_LEVEL) in the "don't delete it?" sense;
425 ;;; this function is a sort of literal translation of those tests into
428 ;;; FIXME: After things settle down, bare :TOP-LEVEL might go away, at
429 ;;; which time it might be possible to replace the COMPONENT-KIND
430 ;;; :TOP-LEVEL mess with a flag COMPONENT-HAS-EXTERNAL-REFERENCES-P
431 ;;; along the lines of FUNCTIONAL-HAS-EXTERNAL-REFERENCES-P.
432 (defun lambda-top-levelish-p (clambda)
433 (or (eql (lambda-kind clambda) :top-level)
434 (lambda-has-external-references-p clambda)))
435 (defun component-top-levelish-p (component)
436 (member (component-kind component)
437 '(:top-level :complex-top-level)))
439 ;;; A CLEANUP structure represents some dynamic binding action. Blocks
440 ;;; are annotated with the current CLEANUP so that dynamic bindings
441 ;;; can be removed when control is transferred out of the binding
442 ;;; environment. We arrange for changes in dynamic bindings to happen
443 ;;; at block boundaries, so that cleanup code may easily be inserted.
444 ;;; The "mess-up" action is explicitly represented by a funny function
445 ;;; call or ENTRY node.
447 ;;; We guarantee that CLEANUPs only need to be done at block boundaries
448 ;;; by requiring that the exit continuations initially head their
449 ;;; blocks, and then by not merging blocks when there is a cleanup
451 (defstruct (cleanup (:copier nil))
452 ;; the kind of thing that has to be cleaned up
453 (kind (required-argument)
454 :type (member :special-bind :catch :unwind-protect :block :tagbody))
455 ;; the node that messes things up. This is the last node in the
456 ;; non-messed-up environment. Null only temporarily. This could be
457 ;; deleted due to unreachability.
458 (mess-up nil :type (or node null))
459 ;; a list of all the NLX-INFO structures whose NLX-INFO-CLEANUP is
460 ;; this cleanup. This is filled in by physical environment analysis.
461 (nlx-info nil :type list))
462 (defprinter (cleanup :identity t)
465 (nlx-info :test nlx-info))
467 ;;; A PHYSENV represents the result of physical environment analysis.
469 ;;; As far as I can tell from reverse engineering, this IR1 structure
470 ;;; represents the physical environment (which is probably not the
471 ;;; standard Lispy term for this concept, but I dunno what is the
472 ;;; standard term): those things in the lexical environment which a
473 ;;; LAMBDA actually interacts with. Thus in
474 ;;; (DEFUN FROB-THINGS (THINGS)
475 ;;; (DOLIST (THING THINGS)
476 ;;; (BLOCK FROBBING-ONE-THING
477 ;;; (MAPCAR (LAMBDA (PATTERN)
478 ;;; (WHEN (FITS-P THING PATTERN)
479 ;;; (RETURN-FROM FROB-THINGS (LIST :FIT THING PATTERN))))
481 ;;; the variables THINGS, THING, and PATTERN and the block names
482 ;;; FROB-THINGS and FROBBING-ONE-THING are all in the inner LAMBDA's
483 ;;; lexical environment, but of those only THING, PATTERN, and
484 ;;; FROB-THINGS are in its physical environment. In IR1, we largely
485 ;;; just collect the names of these things; in IR2 an IR2-PHYSENV
486 ;;; structure is attached to INFO and used to keep track of
487 ;;; associations between these names and less-abstract things (like
488 ;;; TNs, or eventually stack slots and registers). -- WHN 2001-09-29
489 (defstruct (physenv (:copier nil))
490 ;; the function that allocates this physical environment
491 (function (required-argument) :type clambda)
492 #| ; seems not to be used as of sbcl-0.pre7.51
493 ;; a list of all the lambdas that allocate variables in this
494 ;; physical environment
495 (lambdas nil :type list)
497 ;; This ultimately converges to a list of all the LAMBDA-VARs and
498 ;; NLX-INFOs needed from enclosing environments by code in this
499 ;; physical environment. In the meantime, it may be
500 ;; * NIL at object creation time
501 ;; * a superset of the correct result, generated somewhat later
502 ;; * smaller and smaller sets converging to the correct result as
503 ;; we notice and delete unused elements in the superset
504 (closure nil :type list)
505 ;; a list of NLX-INFO structures describing all the non-local exits
506 ;; into this physical environment
507 (nlx-info nil :type list)
508 ;; some kind of info used by the back end
510 (defprinter (physenv :identity t)
512 (closure :test closure)
513 (nlx-info :test nlx-info))
515 ;;; An TAIL-SET structure is used to accumulate information about
516 ;;; tail-recursive local calls. The "tail set" is effectively the
517 ;;; transitive closure of the "is called tail-recursively by"
520 ;;; All functions in the same tail set share the same TAIL-SET
521 ;;; structure. Initially each function has its own TAIL-SET, but when
522 ;;; IR1-OPTIMIZE-RETURN notices a tail local call, it joins the tail
523 ;;; sets of the called function and the calling function.
525 ;;; The tail set is somewhat approximate, because it is too early to
526 ;;; be sure which calls will be tail-recursive. Any call that *might*
527 ;;; end up tail-recursive causes TAIL-SET merging.
528 (defstruct (tail-set)
529 ;; a list of all the LAMBDAs in this tail set
530 (functions nil :type list)
531 ;; our current best guess of the type returned by these functions.
532 ;; This is the union across all the functions of the return node's
533 ;; RESULT-TYPE, excluding local calls.
534 (type *wild-type* :type ctype)
535 ;; some info used by the back end
537 (defprinter (tail-set :identity t)
542 ;;; The NLX-Info structure is used to collect various information
543 ;;; about non-local exits. This is effectively an annotation on the
544 ;;; CONTINUATION, although it is accessed by searching in the
545 ;;; PHYSENV-NLX-INFO.
546 (def!struct (nlx-info (:make-load-form-fun ignore-it))
547 ;; the cleanup associated with this exit. In a catch or
548 ;; unwind-protect, this is the :CATCH or :UNWIND-PROTECT cleanup,
549 ;; and not the cleanup for the escape block. The CLEANUP-KIND of
550 ;; this thus provides a good indication of what kind of exit is
552 (cleanup (required-argument) :type cleanup)
553 ;; the continuation exited to (the CONT of the EXIT nodes). If this
554 ;; exit is from an escape function (CATCH or UNWIND-PROTECT), then
555 ;; physical environment analysis deletes the escape function and
556 ;; instead has the %NLX-ENTRY use this continuation.
558 ;; This slot is primarily an indication of where this exit delivers
559 ;; its values to (if any), but it is also used as a sort of name to
560 ;; allow us to find the NLX-Info that corresponds to a given exit.
561 ;; For this purpose, the Entry must also be used to disambiguate,
562 ;; since exits to different places may deliver their result to the
563 ;; same continuation.
564 (continuation (required-argument) :type continuation)
565 ;; the entry stub inserted by physical environment analysis. This is
566 ;; a block containing a call to the %NLX-Entry funny function that
567 ;; has the original exit destination as its successor. Null only
569 (target nil :type (or cblock null))
570 ;; some kind of info used by the back end
572 (defprinter (nlx-info :identity t)
579 ;;; Variables, constants and functions are all represented by LEAF
580 ;;; structures. A reference to a LEAF is indicated by a REF node. This
581 ;;; allows us to easily substitute one for the other without actually
582 ;;; hacking the flow graph.
583 (def!struct (leaf (:make-load-form-fun ignore-it)
585 ;; some name for this leaf. The exact significance of the name
586 ;; depends on what kind of leaf it is. In a LAMBDA-VAR or
587 ;; GLOBAL-VAR, this is the symbol name of the variable. In a
588 ;; functional that is from a DEFUN, this is the defined name. In
589 ;; other functionals, this is a descriptive string.
591 ;; the type which values of this leaf must have
592 (type *universal-type* :type ctype)
593 ;; where the TYPE information came from:
594 ;; :DECLARED, from a declaration.
595 ;; :ASSUMED, from uses of the object.
596 ;; :DEFINED, from examination of the definition.
597 ;; FIXME: This should be a named type. (LEAF-WHERE-FROM? Or
598 ;; perhaps just WHERE-FROM, since it's not just used in LEAF,
599 ;; but also in various DEFINE-INFO-TYPEs in globaldb.lisp,
600 ;; and very likely elsewhere too.)
601 (where-from :assumed :type (member :declared :assumed :defined))
602 ;; list of the REF nodes for this leaf
604 ;; true if there was ever a REF or SET node for this leaf. This may
605 ;; be true when REFS and SETS are null, since code can be deleted.
606 (ever-used nil :type boolean)
607 ;; some kind of info used by the back end
610 ;;; The CONSTANT structure is used to represent known constant values.
611 ;;; If NAME is not null, then it is the name of the named constant
612 ;;; which this leaf corresponds to, otherwise this is an anonymous
614 (def!struct (constant (:include leaf))
615 ;; the value of the constant
617 (defprinter (constant :identity t)
621 ;;; The BASIC-VAR structure represents information common to all
622 ;;; variables which don't correspond to known local functions.
623 (def!struct (basic-var (:include leaf) (:constructor nil))
624 ;; Lists of the set nodes for this variable.
625 (sets () :type list))
627 ;;; The GLOBAL-VAR structure represents a value hung off of the symbol
628 ;;; NAME. We use a :CONSTANT VAR when we know that the thing is a
629 ;;; constant, but don't know what the value is at compile time.
630 (def!struct (global-var (:include basic-var))
631 ;; kind of variable described
632 (kind (required-argument)
633 :type (member :special :global-function :constant :global)))
634 (defprinter (global-var :identity t)
636 (type :test (not (eq type *universal-type*)))
637 (where-from :test (not (eq where-from :assumed)))
640 ;;; The SLOT-ACCESSOR structure represents slot accessor functions. It
641 ;;; is a subtype of GLOBAL-VAR to make it look more like a normal
643 (def!struct (slot-accessor (:include global-var
644 (where-from :defined)
645 (kind :global-function)))
646 ;; The description of the structure that this is an accessor for.
647 (for (required-argument) :type sb!xc:class)
648 ;; The slot description of the slot.
649 (slot (required-argument)))
650 (defprinter (slot-accessor :identity t)
655 ;;; A DEFINED-FUN represents a function that is defined in the same
656 ;;; compilation block, or that has an inline expansion, or that has a
657 ;;; non-NIL INLINEP value. Whenever we change the INLINEP state (i.e.
658 ;;; an inline proclamation) we copy the structure so that former
659 ;;; INLINEP values are preserved.
660 (def!struct (defined-fun (:include global-var
661 (where-from :defined)
662 (kind :global-function)))
663 ;; The values of INLINEP and INLINE-EXPANSION initialized from the
664 ;; global environment.
665 (inlinep nil :type inlinep)
666 (inline-expansion nil :type (or cons null))
667 ;; the block-local definition of this function (either because it
668 ;; was semi-inline, or because it was defined in this block). If
669 ;; this function is not an entry point, then this may be deleted or
670 ;; LET-converted. Null if we haven't converted the expansion yet.
671 (functional nil :type (or functional null)))
672 (defprinter (defined-fun :identity t)
675 (functional :test functional))
679 ;;; We default the WHERE-FROM and TYPE slots to :DEFINED and FUNCTION.
680 ;;; We don't normally manipulate function types for defined functions,
681 ;;; but if someone wants to know, an approximation is there.
682 (def!struct (functional (:include leaf
683 (where-from :defined)
684 (type (specifier-type 'function))))
685 ;; some information about how this function is used. These values
689 ;; an ordinary function, callable using local call
692 ;; a lambda that is used in only one local call, and has in
693 ;; effect been substituted directly inline. The return node is
694 ;; deleted, and the result is computed with the actual result
695 ;; continuation for the call.
698 ;; Similar to :LET, but the call is an MV-CALL.
701 ;; similar to a LET, but can have other than one call as long as
702 ;; there is at most one non-tail call.
705 ;; a lambda that is an entry-point for an optional-dispatch.
706 ;; Similar to NIL, but requires greater caution, since local call
707 ;; analysis may create new references to this function. Also, the
708 ;; function cannot be deleted even if it has *no* references. The
709 ;; OPTIONAL-DISPATCH is in the LAMDBA-OPTIONAL-DISPATCH.
712 ;; an external entry point lambda. The function it is an entry
713 ;; for is in the ENTRY-FUNCTION slot.
716 ;; a top-level lambda, holding a compiled top-level form.
717 ;; Compiled very much like NIL, but provides an indication of
718 ;; top-level context. A top-level lambda should have *no*
719 ;; references. Its Entry-Function is a self-pointer.
722 ;; After a component is compiled, we clobber any top-level code
723 ;; references to its non-closure XEPs with dummy FUNCTIONAL
724 ;; structures having this kind. This prevents the retained
725 ;; top-level code from holding onto the IR for the code it
730 ;; special functions used internally by CATCH and UNWIND-PROTECT.
731 ;; These are pretty much like a normal function (NIL), but are
732 ;; treated specially by local call analysis and stuff. Neither
733 ;; kind should ever be given an XEP even though they appear as
734 ;; args to funny functions. An :ESCAPE function is never actually
735 ;; called, and thus doesn't need to have code generated for it.
738 ;; This function has been found to be uncallable, and has been
739 ;; marked for deletion.
740 (kind nil :type (member nil :optional :deleted :external :top-level
741 :escape :cleanup :let :mv-let :assignment
743 ;; Is this a function that some external entity (e.g. the fasl dumper)
744 ;; refers to, so that even when it appears to have no references, it
745 ;; shouldn't be deleted? In the old days (before
746 ;; sbcl-0.pre7.37.flaky5.2) this was sort of implicitly true when
747 ;; KIND was :TOP-LEVEL. Now it must be set explicitly, both for
748 ;; :TOP-LEVEL functions and for any other kind of functions that we
749 ;; want to dump or return from #'CL:COMPILE or whatever.
750 (has-external-references-p nil)
751 ;; In a normal function, this is the external entry point (XEP)
752 ;; lambda for this function, if any. Each function that is used
753 ;; other than in a local call has an XEP, and all of the
754 ;; non-local-call references are replaced with references to the
757 ;; In an XEP lambda (indicated by the :EXTERNAL kind), this is the
758 ;; function that the XEP is an entry-point for. The body contains
759 ;; local calls to all the actual entry points in the function. In a
760 ;; :TOP-LEVEL lambda (which is its own XEP) this is a self-pointer.
762 ;; With all other kinds, this is null.
763 (entry-function nil :type (or functional null))
764 ;; the value of any inline/notinline declaration for a local function
765 (inlinep nil :type inlinep)
766 ;; If we have a lambda that can be used as in inline expansion for
767 ;; this function, then this is it. If there is no source-level
768 ;; lambda corresponding to this function then this is Null (but then
769 ;; INLINEP will always be NIL as well.)
770 (inline-expansion nil :type list)
771 ;; the lexical environment that the inline-expansion should be converted in
772 (lexenv *lexenv* :type lexenv)
773 ;; the original function or macro lambda list, or :UNSPECIFIED if
774 ;; this is a compiler created function
775 (arg-documentation nil :type (or list (member :unspecified)))
776 ;; various rare miscellaneous info that drives code generation & stuff
777 (plist () :type list))
778 (defprinter (functional :identity t)
781 ;;; The CLAMBDA only deals with required lexical arguments. Special,
782 ;;; optional, keyword and rest arguments are handled by transforming
783 ;;; into simpler stuff.
784 (def!struct (clambda (:include functional)
786 (:predicate lambda-p)
787 (:constructor make-lambda)
788 (:copier copy-lambda))
789 ;; list of LAMBDA-VAR descriptors for args
790 (vars nil :type list)
791 ;; If this function was ever a :OPTIONAL function (an entry-point
792 ;; for an OPTIONAL-DISPATCH), then this is that OPTIONAL-DISPATCH.
793 ;; The optional dispatch will be :DELETED if this function is no
795 (optional-dispatch nil :type (or optional-dispatch null))
796 ;; the BIND node for this LAMBDA. This node marks the beginning of
797 ;; the lambda, and serves to explicitly represent the lambda binding
798 ;; semantics within the flow graph representation. This is null in
799 ;; deleted functions, and also in LETs where we deleted the call and
800 ;; bind (because there are no variables left), but have not yet
801 ;; actually deleted the LAMBDA yet.
802 (bind nil :type (or bind null))
803 ;; the RETURN node for this LAMBDA, or NIL if it has been deleted.
804 ;; This marks the end of the lambda, receiving the result of the
805 ;; body. In a LET, the return node is deleted, and the body delivers
806 ;; the value to the actual continuation. The return may also be
807 ;; deleted if it is unreachable.
808 (return nil :type (or creturn null))
809 ;; If this CLAMBDA is a LET, then this slot holds the LAMBDA whose
810 ;; LETS list we are in, otherwise it is a self-pointer.
811 (home nil :type (or clambda null))
812 ;; a list of all the all the lambdas that have been LET-substituted
813 ;; in this lambda. This is only non-null in lambdas that aren't
816 ;; a list of all the ENTRY nodes in this function and its LETs, or
818 (entries () :type list)
819 ;; a list of all the functions directly called from this function
820 ;; (or one of its LETs) using a non-LET local call. This may include
821 ;; deleted functions because nobody bothers to clear them out.
822 (calls () :type list)
823 ;; the TAIL-SET that this LAMBDA is in. This is null during creation.
825 ;; In CMU CL, and old SBCL, this was also NILed out when LET
826 ;; conversion happened. That caused some problems, so as of
827 ;; sbcl-0.pre7.37.flaky5.2 when I was trying to get the compiler to
828 ;; emit :EXTERNAL functions directly, and so now the value
829 ;; is no longer NILed out in LET conversion, but instead copied
830 ;; (so that any further optimizations on the rest of the tail
831 ;; set won't modify the value) if necessary.
832 (tail-set nil :type (or tail-set null))
833 ;; the structure which represents the phsical environment that this
834 ;; function's variables are allocated in. This is filled in by
835 ;; physical environment analysis. In a LET, this is EQ to our home's
836 ;; physical environment.
837 (physenv nil :type (or physenv null))
838 ;; In a LET, this is the NODE-LEXENV of the combination node. We
839 ;; retain it so that if the LET is deleted (due to a lack of vars),
840 ;; we will still have caller's lexenv to figure out which cleanup is
842 (call-lexenv nil :type (or lexenv null)))
843 (defprinter (clambda :conc-name lambda- :identity t)
845 (type :test (not (eq type *universal-type*)))
846 (where-from :test (not (eq where-from :assumed)))
847 (vars :prin1 (mapcar #'leaf-name vars)))
849 ;;; The OPTIONAL-DISPATCH leaf is used to represent hairy lambdas. It
850 ;;; is a FUNCTIONAL, like LAMBDA. Each legal number of arguments has a
851 ;;; function which is called when that number of arguments is passed.
852 ;;; The function is called with all the arguments actually passed. If
853 ;;; additional arguments are legal, then the LEXPR style MORE-ENTRY
854 ;;; handles them. The value returned by the function is the value
855 ;;; which results from calling the OPTIONAL-DISPATCH.
857 ;;; The theory is that each entry-point function calls the next entry
858 ;;; point tail-recursively, passing all the arguments passed in and
859 ;;; the default for the argument the entry point is for. The last
860 ;;; entry point calls the real body of the function. In the presence
861 ;;; of SUPPLIED-P args and other hair, things are more complicated. In
862 ;;; general, there is a distinct internal function that takes the
863 ;;; SUPPLIED-P args as parameters. The preceding entry point calls
864 ;;; this function with NIL filled in for the SUPPLIED-P args, while
865 ;;; the current entry point calls it with T in the SUPPLIED-P
868 ;;; Note that it is easy to turn a call with a known number of
869 ;;; arguments into a direct call to the appropriate entry-point
870 ;;; function, so functions that are compiled together can avoid doing
872 (def!struct (optional-dispatch (:include functional))
873 ;; the original parsed argument list, for anyone who cares
874 (arglist nil :type list)
875 ;; true if &ALLOW-OTHER-KEYS was supplied
876 (allowp nil :type boolean)
877 ;; true if &KEY was specified (which doesn't necessarily mean that
878 ;; there are any &KEY arguments..)
879 (keyp nil :type boolean)
880 ;; the number of required arguments. This is the smallest legal
881 ;; number of arguments.
882 (min-args 0 :type unsigned-byte)
883 ;; the total number of required and optional arguments. Args at
884 ;; positions >= to this are &REST, &KEY or illegal args.
885 (max-args 0 :type unsigned-byte)
886 ;; list of the LAMBDAs which are the entry points for non-rest,
887 ;; non-key calls. The entry for MIN-ARGS is first, MIN-ARGS+1
888 ;; second, ... MAX-ARGS last. The last entry-point always calls the
889 ;; main entry; in simple cases it may be the main entry.
890 (entry-points nil :type list)
891 ;; an entry point which takes MAX-ARGS fixed arguments followed by
892 ;; an argument context pointer and an argument count. This entry
893 ;; point deals with listifying rest args and parsing keywords. This
894 ;; is null when extra arguments aren't legal.
895 (more-entry nil :type (or clambda null))
896 ;; the main entry-point into the function, which takes all arguments
897 ;; including keywords as fixed arguments. The format of the
898 ;; arguments must be determined by examining the arglist. This may
899 ;; be used by callers that supply at least MAX-ARGS arguments and
900 ;; know what they are doing.
901 (main-entry nil :type (or clambda null)))
902 (defprinter (optional-dispatch :identity t)
904 (type :test (not (eq type *universal-type*)))
905 (where-from :test (not (eq where-from :assumed)))
911 (entry-points :test entry-points)
912 (more-entry :test more-entry)
915 ;;; The ARG-INFO structure allows us to tack various information onto
916 ;;; LAMBDA-VARs during IR1 conversion. If we use one of these things,
917 ;;; then the var will have to be massaged a bit before it is simple
920 ;; true if this arg is to be specially bound
921 (specialp nil :type boolean)
922 ;; the kind of argument being described. Required args only have arg
923 ;; info structures if they are special.
924 (kind (required-argument) :type (member :required :optional :keyword :rest
925 :more-context :more-count))
926 ;; If true, this is the VAR for SUPPLIED-P variable of a keyword or
927 ;; optional arg. This is true for keywords with non-constant
928 ;; defaults even when there is no user-specified supplied-p var.
929 (supplied-p nil :type (or lambda-var null))
930 ;; the default for a keyword or optional, represented as the
931 ;; original Lisp code. This is set to NIL in &KEY arguments that are
932 ;; defaulted using the SUPPLIED-P arg.
933 (default nil :type t)
934 ;; the actual key for a &KEY argument. Note that in ANSI CL this is not
935 ;; necessarily a keyword: (DEFUN FOO (&KEY ((BAR BAR))) ..).
936 (key nil :type symbol))
937 (defprinter (arg-info :identity t)
938 (specialp :test specialp)
940 (supplied-p :test supplied-p)
941 (default :test default)
944 ;;; The LAMBDA-VAR structure represents a lexical lambda variable.
945 ;;; This structure is also used during IR1 conversion to describe
946 ;;; lambda arguments which may ultimately turn out not to be simple
949 ;;; LAMBDA-VARs with no REFs are considered to be deleted; physical
950 ;;; environment analysis isn't done on these variables, so the back
951 ;;; end must check for and ignore unreferenced variables. Note that a
952 ;;; deleted lambda-var may have sets; in this case the back end is
953 ;;; still responsible for propagating the Set-Value to the set's Cont.
954 (def!struct (lambda-var (:include basic-var))
955 ;; true if this variable has been declared IGNORE
956 (ignorep nil :type boolean)
957 ;; the CLAMBDA that this var belongs to. This may be null when we are
958 ;; building a lambda during IR1 conversion.
959 (home nil :type (or null clambda))
960 ;; This is set by physical environment analysis if it chooses an
961 ;; indirect (value cell) representation for this variable because it
962 ;; is both set and closed over.
963 (indirect nil :type boolean)
964 ;; The following two slots are only meaningful during IR1 conversion
965 ;; of hairy lambda vars:
967 ;; The ARG-INFO structure which holds information obtained from
969 (arg-info nil :type (or arg-info null))
970 ;; if true, the GLOBAL-VAR structure for the special variable which
971 ;; is to be bound to the value of this argument
972 (specvar nil :type (or global-var null))
973 ;; Set of the CONSTRAINTs on this variable. Used by constraint
974 ;; propagation. This is left null by the lambda pre-pass if it
975 ;; determine that this is a set closure variable, and is thus not a
976 ;; good subject for flow analysis.
977 (constraints nil :type (or sset null)))
978 (defprinter (lambda-var :identity t)
980 (type :test (not (eq type *universal-type*)))
981 (where-from :test (not (eq where-from :assumed)))
982 (ignorep :test ignorep)
983 (arg-info :test arg-info)
984 (specvar :test specvar))
986 ;;;; basic node types
988 ;;; A REF represents a reference to a LEAF. REF-REOPTIMIZE is
989 ;;; initially (and forever) NIL, since REFs don't receive any values
990 ;;; and don't have any IR1 optimizer.
991 (defstruct (ref (:include node (:reoptimize nil))
992 (:constructor make-ref (derived-type leaf))
994 ;; The leaf referenced.
995 (leaf nil :type leaf))
996 (defprinter (ref :identity t)
999 ;;; Naturally, the IF node always appears at the end of a block.
1000 ;;; NODE-CONT is a dummy continuation, and is there only to keep
1002 (defstruct (cif (:include node)
1005 (:constructor make-if)
1007 ;; CONTINUATION for the predicate
1008 (test (required-argument) :type continuation)
1009 ;; the blocks that we execute next in true and false case,
1010 ;; respectively (may be the same)
1011 (consequent (required-argument) :type cblock)
1012 (alternative (required-argument) :type cblock))
1013 (defprinter (cif :conc-name if- :identity t)
1014 (test :prin1 (continuation-use test))
1018 (defstruct (cset (:include node
1019 (derived-type *universal-type*))
1022 (:constructor make-set)
1024 ;; descriptor for the variable set
1025 (var (required-argument) :type basic-var)
1026 ;; continuation for the value form
1027 (value (required-argument) :type continuation))
1028 (defprinter (cset :conc-name set- :identity t)
1030 (value :prin1 (continuation-use value)))
1032 ;;; The BASIC-COMBINATION structure is used to represent both normal
1033 ;;; and multiple value combinations. In a local function call, this
1034 ;;; node appears at the end of its block and the body of the called
1035 ;;; function appears as the successor. The NODE-CONT remains the
1036 ;;; continuation which receives the value of the call.
1037 (defstruct (basic-combination (:include node)
1040 ;; continuation for the function
1041 (fun (required-argument) :type continuation)
1042 ;; list of CONTINUATIONs for the args. In a local call, an argument
1043 ;; continuation may be replaced with NIL to indicate that the
1044 ;; corresponding variable is unreferenced, and thus no argument
1045 ;; value need be passed.
1046 (args nil :type list)
1047 ;; the kind of function call being made. :LOCAL means that this is a
1048 ;; local call to a function in the same component, and that argument
1049 ;; syntax checking has been done, etc. Calls to known global
1050 ;; functions are represented by storing the FUNCTION-INFO for the
1051 ;; function in this slot. :FULL is a call to an (as yet) unknown
1052 ;; function. :ERROR is like :FULL, but means that we have discovered
1053 ;; that the call contains an error, and should not be reconsidered
1054 ;; for optimization.
1055 (kind :full :type (or (member :local :full :error) function-info))
1056 ;; some kind of information attached to this node by the back end
1059 ;;; The COMBINATION node represents all normal function calls,
1060 ;;; including FUNCALL. This is distinct from BASIC-COMBINATION so that
1061 ;;; an MV-COMBINATION isn't COMBINATION-P.
1062 (defstruct (combination (:include basic-combination)
1063 (:constructor make-combination (fun))
1065 (defprinter (combination :identity t)
1066 (fun :prin1 (continuation-use fun))
1067 (args :prin1 (mapcar (lambda (x)
1069 (continuation-use x)
1073 ;;; An MV-COMBINATION is to MULTIPLE-VALUE-CALL as a COMBINATION is to
1074 ;;; FUNCALL. This is used to implement all the multiple-value
1075 ;;; receiving forms.
1076 (defstruct (mv-combination (:include basic-combination)
1077 (:constructor make-mv-combination (fun))
1079 (defprinter (mv-combination)
1080 (fun :prin1 (continuation-use fun))
1081 (args :prin1 (mapcar #'continuation-use args)))
1083 ;;; The BIND node marks the beginning of a lambda body and represents
1084 ;;; the creation and initialization of the variables.
1085 (defstruct (bind (:include node)
1087 ;; the lambda we are binding variables for. Null when we are
1088 ;; creating the LAMBDA during IR1 translation.
1089 (lambda nil :type (or clambda null)))
1093 ;;; The RETURN node marks the end of a lambda body. It collects the
1094 ;;; return values and represents the control transfer on return. This
1095 ;;; is also where we stick information used for TAIL-SET type
1097 (defstruct (creturn (:include node)
1098 (:conc-name return-)
1099 (:predicate return-p)
1100 (:constructor make-return)
1101 (:copier copy-return))
1102 ;; the lambda we are returning from. Null temporarily during
1104 (lambda nil :type (or clambda null))
1105 ;; the continuation which yields the value of the lambda
1106 (result (required-argument) :type continuation)
1107 ;; the union of the node-derived-type of all uses of the result
1108 ;; other than by a local call, intersected with the result's
1109 ;; asserted-type. If there are no non-call uses, this is
1111 (result-type *wild-type* :type ctype))
1112 (defprinter (creturn :conc-name return- :identity t)
1116 ;;;; non-local exit support
1118 ;;;; In IR1, we insert special nodes to mark potentially non-local
1121 ;;; The ENTRY node serves to mark the start of the dynamic extent of a
1122 ;;; lexical exit. It is the mess-up node for the corresponding :Entry
1124 (defstruct (entry (:include node)
1126 ;; All of the Exit nodes for potential non-local exits to this point.
1127 (exits nil :type list)
1128 ;; The cleanup for this entry. NULL only temporarily.
1129 (cleanup nil :type (or cleanup null)))
1130 (defprinter (entry :identity t))
1132 ;;; The EXIT node marks the place at which exit code would be emitted,
1133 ;;; if necessary. This is interposed between the uses of the exit
1134 ;;; continuation and the exit continuation's DEST. Instead of using
1135 ;;; the returned value being delivered directly to the exit
1136 ;;; continuation, it is delivered to our VALUE continuation. The
1137 ;;; original exit continuation is the exit node's CONT.
1138 (defstruct (exit (:include node)
1140 ;; The Entry node that this is an exit for. If null, this is a
1141 ;; degenerate exit. A degenerate exit is used to "fill" an empty
1142 ;; block (which isn't allowed in IR1.) In a degenerate exit, Value
1143 ;; is always also null.
1144 (entry nil :type (or entry null))
1145 ;; The continuation yeilding the value we are to exit with. If NIL,
1146 ;; then no value is desired (as in GO).
1147 (value nil :type (or continuation null)))
1148 (defprinter (exit :identity t)
1150 (value :test value))
1152 ;;;; miscellaneous IR1 structures
1154 (defstruct (undefined-warning
1155 #-no-ansi-print-object
1156 (:print-object (lambda (x s)
1157 (print-unreadable-object (x s :type t)
1158 (prin1 (undefined-warning-name x) s))))
1160 ;; the name of the unknown thing
1161 (name nil :type (or symbol list))
1162 ;; the kind of reference to NAME
1163 (kind (required-argument) :type (member :function :type :variable))
1164 ;; the number of times this thing was used
1165 (count 0 :type unsigned-byte)
1166 ;; a list of COMPILER-ERROR-CONTEXT structures describing places
1167 ;; where this thing was used. Note that we only record the first
1168 ;; *UNDEFINED-WARNING-LIMIT* calls.
1169 (warnings () :type list))
1171 ;;; a helper for the POLICY macro, defined late here so that the
1172 ;;; various type tests can be inlined
1173 (declaim (ftype (function ((or list lexenv node functional)) list)
1175 (defun %coerce-to-policy (thing)
1176 (let ((result (etypecase thing
1178 (lexenv (lexenv-policy thing))
1179 (node (lexenv-policy (node-lexenv thing)))
1180 (functional (lexenv-policy (functional-lexenv thing))))))
1181 ;; Test the first element of the list as a rudimentary sanity
1182 ;; that it really does look like a valid policy.
1183 (aver (or (null result) (policy-quality-name-p (caar result))))
1187 ;;;; Freeze some structure types to speed type testing.
1190 (declaim (freeze-type node leaf lexenv continuation cblock component cleanup
1191 physenv tail-set nlx-info))